Nearctica - Eastern Wildflowers - Onagraceae - Small-flowered Evening Primrose

Small-flowered Evening Primrose

Oenothera parviflora

Line Drawing: Britton, N.L., and A. Brown. 1913. An Illustrated Flora of the Northern United States and Canada, Second Edition.

Small-flowered Evening Primrose (Oenothera parviflora L.)

Identification: Flowers yellow, large (about 1 inch in diameter), with 4 petals and 8 stamens. Stigma with 4 lobes, cross-shaped. Calyx with 4 sepals, the sepals bent downward (reflexed). Flowers buds not completely covered nor enclosed by the sepals, usually some yellow from the petals showing through. Seed capsules narrow, elongate, sessile to the stem in the leaf axils. Stem usually not branched, not tinged with dark red, although red hairs may be present. Leaves crowded on the stem, elongate, narrow, and with ragged outer margins. Plant 1 to 4 feet in height.

Distribution: Southeastern Canada and the northeastern United States, southward to Missouri and North Carolina.

Habitat: Small-flowered Evening Primrose is found on dry or sandy soils in open spaces.

Flowering period: August to October.

Similar Species: Common Evening Primrose is very difficult to separate from Small-flowered Evening Primrose. The flowers of Small-flowered Evening Primrose are usually smaller (about 1 inch in diameter) compared to the 1 to 2 inches flowers of Common Evening Primrose. The stem of Common Evening Primrose is typically heavily branched. The flower bud of Common Evening Primrose is completely encased by the sepals, but the sepals of Small-flowered Evening Primrose usually are slightly spread with the yellow of the petals showing through.

Comments: The flowers of Small-flowered Evening Primrose open in the early evening and wilt by noon of the following day. A variety with narrow petals (as in the drawing on the left) has historically gone by the name Oenothera cruciata.